System of train control.



G. P. THURBER.

SYSTEM OF TRAIN CONTROL.

APPLICATION FILED NOV. 5. I908- RENEWED APR. 29, 1915.

Km m m .w w. n m M fi d w m m H. m m A pm .1 Q U m w P h H H. H. Em E E Fm MM mm qw U v N www E q M S Q ms m w m 1 \NN WW 1 Patented Dec. 7, 1915." 4 SHEETS-SHEET 2 WITNESSES IE9 I G. P. THURBER; .SYSTEM OF IRAIN'CONTROL. APPLICATION min NOV. 5'. IQOBL EMWED APR. 29. 1915. Patented Dec! 7, 1915 S 4 SHEETS-SHEET 3- 3 WI T WITNESSES l/VI/E/VTOR (M /Sm ww ll TTORN E KY G. P. THURBER. SYSTEM OF TRAIN CONTROL.

APPLICATION FILED NOV. 5. 190B. RENEWED APR. 29. 1915.

Patented Dec. 7, 1915.

4 SHEETS-*SHEET 4- B! y (7M0, r fiww M ATTOIMIE VJ? GUY P. THURBER, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO AUTOMATIC TRAIN CONTROL & SIGNAL COMPANY, OF PITTSBURGH, PENNSYLVANIA. A CORPORATION OF DELAWARE.

SYSTEM OF TRAIN CONTROL.

Specification of Letters Patent.

Patented Dec. '7, 1915..

Application fi1ed November 5, 1908, Serial No. 461,141. Renewed April 29, 1915. Serial No. 24,795.

To all whom it may concern Be it'k'nown that I, GUY P. THURBER, citizen of the United States, and resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Systems of Train Control, of which the following is a specification.

The present invention relates to a system of train control.

The primary object of the invention is to produce a system which will not only indi cate abnormal track conditions, but which will also give warning of its own imperfection or breakdown, and this Without the use of third-rail or similar devices, the traffic track itself constituting a part of the system.

Other objects will appear as the specification proceeds.

The mai feature of the invention centers around a main circuit normally closed and charged, which extends partly through conductors carr ed by the train and is normally closed through the traffic tracks. The traffic tracks are divided into sections or blocks by insulation, and a normally closed blind shunt or jumper circuit connects adjacent sections of the track. The main circuit is completed through this blind shunt under normal conditions when passing freain'one section to another. If the blind shunt is broken, the main circuit is broken when passing over the insulation. Under the control of the main circuit are suitable train controlling means, such as signaling devices or throttle and air-brake controlling means, or both. These train controlling means are normally held inoperative, that is to say: so long as the main circuit remains closed and charged. When this circuit is broken these train controlling means become operative and act, according to their capacity, to give signals or to stop the train. The energizing battery for the main circuit is, in the form disclosed, carried. by the moving train. Preferably the train controlling means are not directly under the control of the main circuit, but are controlled by means of one or .more subsidiary cab circuits normally held closed by the main circuit. The integrity of the, main circuit thus depends upon whether or not the blind shunt is closed. This aside from such conditions as a broken rail in the block in which the train is running or imperfections in the connections carried by the moving train. Accordingly, this blind shunt is under the control of track and line relays of the succeeding blocks, which if any of these relays are deenergized the blind shunt is broken. The arrangement of track and line relays and circuits for accomplishing this may of course vary widely, but in the preferred form these parts take the following form: The track is divided into sections, each section comprising a main and a local block. Both or only one of the rails may be insulated between the main and local blocks of the same section, but both rails must be insulated between the local block of one section and the main block of the adjoining section. Interposed between the local block of one section and the main block of the same section is a blind shunt connection having a relay. Each main and each local2 ljlock is provided with a circuit and relay, and the line circuits extending between the block sections are also provided with relays. The jumper circuit at a certain section is controlled by the main block relay and line relay. The main block circuit is controlled by the local block relay of the succeeding section. The line wires, of which there are four in the form disclosed, are controlled, one set by the shunt or line controlling relays, of two succeeding sections, while the other set is controlled alternately by the main block relay and the shunt relay at the two succeeding sections. Thus the circuits and relays'are interconnected in such a way that a break or a shunt circuiting of any of the circuits, including the traffic tracks, will act to break the blind shunt of two or more sections. When a train therefore arrives at any of these sections the main circuit'of the train is broken and the safety devices made operative.

As it is essential to the proper working i vsition so that if the insulation should break down, the batteries will neutralize each other.

Certain relays or electro-magnets are used inthe systemnvhichwhen deenergized, due

to the rupture of any of the connections or the deflection of the magnetizing current in another direction, serve to break certain 011'- cuits to cause the actuation of the normally lnactive train controlling means. When as under certain conditions, the current is deflected to another path of lower resistance for the purpose of deenergizing the relay or relays, enough current might still flow through the relay to enable it to sustain its armature and to thus defeat the very purpose of the relay which is, to drop its armature and break another circuit when it is itself denergized. To overcome this, I provide a bypath for the current which operates autcmatically to shunt the current around the relay when the relay is to be thus deenergized. I

. In the accompanying drawings, is illustrated the preferred embodiment of. the invention, but various changes may be made without departing from the scope of the invention.

.In the said drawings: Figure 1, is a diagrammatieal view of my complete system, representing a train and a portion of the trafiic track with their respective equipments, the parts of the system being in their normal state, as when the proper running conditions exist. Fig. 2, is a similar view representing the operation of the system as when two trains are in close proximity on the same track. Fig. 3, is a detail view illustratin a slight modification in the connection 0 the battery for energizing the main block relay. Fig. 4, is an enlarged view illustrating the wiring of two of the stations.

Like reference characters designate the same parts throughout the several views.

The cab or train circuit, which maybe called the controlling circuit, is carried by some part of the train, and is preferably, together with the various train controlling means, locatedconveniently in the engineers cab. The circuit is made up of two main conductors 1, a source of electrical supply, which is here shown as a battery 2, and a circuit breaker of some sort, which is preferably in the shape of a relay 3, havin an armature 4. In order to insure a positive break in the circuit when for any reason the main relay is denergized, even if only so temporarily, I prefer to put the armature of the relay in circuit, so that the instant the armature drops, the circuit is broken-and cannot be completed, in so far as the actual cab portion of the circuit isconcerned, until the armature is restored. For this reason the relay has a short backconnection 5, ending in a contact terminal 6, to be engaged by the armature, when the relay is energized to hold its armature in contact with the terminal 6. The relay thus cannot restore its own circuit. The armature is pivoted at the point 7. Train controlling means are either included in this cab or controlling circuit or are included in a subsidiary circuit under the control of the main cab circuit, so that the said controlling means are actually under the control of the main cab circuit, being either directly or indirectly controlled thereby. This train controlling means will be later described in detail.

To render the controlling circuit responsive to track conditions, the said circuit is led to the track and is completed by the traffic track itself, so that any break in the trafiic track acts as a break in the controlling circuit. The controlling circuit is led to the track at two different points, spaced and iiisulated from each other, so that the'traflic track will serveas a conductor for the passage of the current from one point to the other. The circuit is preferably connected to the track at two points, as illustrated in Fig. 1, by insulating two trucks 8, and connecting the ends of the controlling circuit to these insulated trucks.

The track is preferably divided into blocks or sections of any suitable length and this may be done as illustrated in the several views, by placing suitable insulation between the joints at the end of each track section.

The principle of the operation of the invention is illustrated in comprehensive form in Figs. 1, 2 and 4, to which attention is directed. WVhen the train is in any one block, the cab circuit is completed through the traflic rails, provided of course that such rails are electrically continuous. Therefore if no other means were provided, there would be a break in the cab circuit as the trucks passed each insulated joint. To overcome this otherwise inevitable break, a norbridges the gap across the insulated joints when the train is passing from one block into the next. A battery 14, may be placed in the shunt connection to assist the passage of the current to the return side of the cab circuit and for a certain other use which will appear hereinafter. It will be evident that a rupture in the shunt circuit, will cause a break in the cab circuit and the safety devices normally held inoperative by the normally closed circuit, by reason of such break in the circuit, will become operative. The traflic rails or the shunt, therefore in reality, form a continuation of the cab circuit, and a break in any part of this system will serve to render the safety devices active. I therefore use this shunt as a bridge for the cab or controlling circuit under normal conditions and as a means for disrupting the cab circuit to cause actuation of the safety devices under abnormal or danger conditions.

For this purpose, certain devices are used which are affected by track conditions and which control the shunt These devices for controlling the shunt are preferably in the shape of certain circuits which are normally closed when proper running conditions exist, but which automatically open when a change from normal running conditions occurs, these circuits in turn containing relays having armatures which when the relays are energized serve to hold the shunt circuit closed, and which, when the relays are deenergized, create an artificial break in the shunt circuit. These circuits, which might be termed track circuits are dependent for their action upon the condition of different portions of the track, so that as the conditions of these different portions oftrack are altered, the track circuits are affected accordingly, and the shunt circuit likewise.

In order to render the system more eflective, each section of track preferably consists of a long main block 15, and a short local block 16, the two being insulated one from the other. The joints between the local block and the main block of the same section arepreferably staggered as shown at 17. In each local block there is a local circuit 18, including a battery .19, and a local block relay 20. This local block relay controls a double armature or a pair of ararmatures 21 and 22. In each main block, a main block'relay 23, is connected by wires 24, between the opposite rails of the track. Energizing current for the main block relay is derived from a battery 25, which is likewise connected across the rails by conductors 26. This circuit just described and which may be designated as the main block circuit, is under the control of the local block relay, the armature 22, of the local block relay serving, when the local block relay is energized, to engage the contact point 27, and thus close the main circuit. A contact 28, is interposed in the shunt circuit and when the main block relay is energized, the armature 29 of said relay, engages said contact thus serving to close the shunt circuit at that point. There is another contact 30, interposed in the shunt circuit and a corresponding armature 31, to engage this contact, the armature 31, being in turn controlled by the relay 32, which is at the end of the charged line circuit 33. This line .circuit is controlled by the local bloE'relay of the second succeeding section, there being a contact 34, in said circuit adapted to be engaged by the armature 21, of the said local block relay. This line circuit is likewise under the control of a relay 35, located at the same section as the local block relay just referred to. This relay is normally energized by the battery 14, the current from said battery passing along a portion of the shunt connection, to the armature 29, and

thence by the contact 36, and conductor 37, through the relay and by conductors 3826, back to the rail and through the rail to the other pole of the battery. The conductor 26, may serve here as a common return for both this circuit, and the main block circuit. The relay 35, is thus influenced by the shunt connection. The line circuit 33, is also under the control of the relay 35, as the armature 36, of this relay under normal conditions engages the contact 37, in the line wire and serves to complete the line circuit. The line circuit 33, is likewise under the control of the local block relay and the shunt-controlled relay 35, of the next adjoiningsection in the same way as just described. This line circuit just described is preferably used to render caution signals, and the line circuit-39, is preferably used for the rendering of danger signals. v

The line circuit 39, terminates in a relay 10, whose use corresponds to the use of the line circuit relay 32, of the next adjoining section, that is, to complete the shunt circuit by holding the armature 31, in engagement with the contact 30. This second line circuit is energized by a battery 41, and is under the control of the shunt-controlled lix lay 35, of the next adjoining section by means of an armature *2, adapted to be attracted by said relay and to engage the contact 43, in the second line circuit. The second line circuit is also under the control of the main block relay of the second succeeding section and for this purpose a contact 44, is interposed in the circuit which is adapted to be engaged by the armature. 45, of the main block relay 23. This may also be a double armature.

In order to understand the operation of the system, suppose a train to occupy the main block at the left in Fig. 2. This train is diagrammatically represented by the pair of wheels and axles 46. \Vhen in this position the current from the main block battery 25, will be short circuited across the rails by the wheels and axles of the train, thus causing the main block relay 23, to be dei nergized. The said main block relay when so deenergized drops its armature 29, and the shunt connection is broken at the point 28. By this same action the shuntcontrolled relay circuit is broken at the point 36. and the shunt-controlled relay 35, is deenergized. The dei nergization of the shuntcontrolled relay causes the double armature 3(l-'12 of the relay to drop, thereby breaking'the first line circuit 33 (caution), at point 37, and the second line circuit 39, (danger) at the point 43. This break in the first line circuit causes the relay 32, at the second preceding section at the end of this line circuit, to be dei nergized. dropping its armature 31. and breaking the shunt circuit at the point 30, and causes the relay 'mally on open circuit. leading frg n the signal recording sideof 40 at the first preceding section to be deenergized breaking the shunt circuit of that section. Then should a second train come along and reach the second preceding section, where the shunt connection is broken, the cab circuit on the second train cannot be completed through the shunt connection, as it would be, if the track conditions were clear and normal. This break in the shunt portion of the cab circuit causes a caution signal to be displayed in the cab in the following manner: The armature of the cab relay is preferably of compound structure and made in three parts 46, 47 and 48 respectively, so as to establish three different connections, or relatively the. same result might be attained by having a single armature provided with the proper .connections. For the purpose of giving the signals to the engineer, I prefer to use an electro-magnetic indicator 49, which pal-takes of the nature of a semaphore. This indicator when the cab circuit is complete is energized by current preferably from the main cab battery 2, and for this purpose a branch wire 50, is used, which is connected to the main cab' circuit at theflpoint 51. The branch wire after passing through the indicator terminates in a contact 52. to be engaged by the armature 47, of the cab relay, said armature being connected to the other side of the main cab circuit by a short conductor 53, so that in reality the indicator is connected in parallel across the main cab circuit. Therefore when the main cab circuit is broken in the manner before described, or in fact in any manner, the indicator gives a visual warning to the engineer or other authority in charge. In addition to this, I prefer to use a register for recording the giving of such signals to the engineer. This recorder would preferably be in the shape of a watchma-ns clock, such as that shown in Patent No. 822,029, and is indicated at 54. This clock would have two magnets 55 and 56, for recording the giving of signals and the actuation of the train stopping means respectively. The clock is preferably nor- A conductor 57,

the clock, terminates in a contact 58, which when the armature 46, of the cab relay falls, is engaged by said armature and a circuit completed through the clock by way of said armature, the main battery 2, and the conductor 59. As an additional warning to the engineer, I prefer to use an audible alarm such as a whistle 60, this whistle being controlled by an electro-magnetically controlled air valve .61. 'This so-called whistle valve has a solenoidpart 62, which when energized, as it normally is, holds the air valve closed. From the solenoid valve a pair of conductors 63, lead; one of them terminating in a contact 64, normally engaged by the cab relay armature 48, and the other leading to battery 65. A conductor 66, from the opposite side of the battery is connected with the armature 48, and to simplify the wiring somewhat, a portion of the main cab circuit may be utilized as a part of the return conductor of this air valve circuit, and for this reason one of the conductors 63, may be joined to the main cab circuit at point 67.

It will be apparent that when for any reason the cab circuit is broken, the air valve circuit will be broken at the point 64, by reason of the falling of the cab relay armature 48, causing the solenoid 62 to be deenergized, opening the valve 61, and causing the whistle to be sounded. The whistle is supplied with steamor air, preferably air, by means of a branch pipe 68, from a main pipe 69, the main pipe being in suitable communication with the reservoir 70. After the engineer has received the caution signals in this manner, he may, if the train has passed over the insulated joint (which it will probably have done) by pressing a button or actuating a like circuit closing device 71, again restore the cab circuit to its originally closed condition. This restoring device is connected by conductors 72, in shunt around the circuit-breaking armature 4, of the cab relay so that if, as has been supposed, the train has passed the joint and is now on an electrically continuous piece of track, by pressing this button the cab circuit will be completed, the cab relay will be energized, attracting its different armatures and closing all the cab circuits. The engineer should then proceed with caution and if the danger or obstruction has not been removed, when the next insulated joint is reached the cab circuit will again be broken as the shunt circuit will be open at the point 30, due to the deeergization of the second line circuit relay 40, which relay has been deenergized due to the breaking of its circuit at point 43,-as before described. Therefore, assuming the train to have reached this second joint and the shunt circuit to be open as described, the shunt portion of the cab circuit to be open as described, the shunt portion of the cab circuit will again be broken and visual and audible signals will again be given to the engineer. These second signals will also be recorded by the clock so that a perfect check will be kept on the engineers actions.

A predetermined period of time after the signals have been given, a time switch'device 73, in the cab, becomes operative to cause actuation of the means for stop ing the train. This device may partake o the nature of a dash pot and is adjusted to act sequentially after the giving of the signals. Throttle controlling circuit wires 74, are connected to the time switch, one of said Wires having a fixed connection therewith at 75, and the other of the wires having a severable connection therewith at 76. A throttle controlling magnet valve 77 is included in this last circuit which is preferably similar to the valve 61. The magnet valve 77 is normally energized by the battery 65, and to simplify the connections, one of the conductors 74:, may be connected at 67, to the common return of the main cab circuit and the other of the conductors 74,. may be connected at 7 7 66, of the air valve circuit 63. It will be seen that the magnet valves 61 and 77 are in reality connected in parallel and both supplied with current from the battery 65, which for this purpose is preferably arranged in multiple-series as shown in the drawings, so as to supply the proper energizing current to both magnet valves. By means of the branch pipe 78, leading from the air valve 61, air is supplied to the time switch 73, and under normal conditions the upper or switch portion of the time switch 7 is upheld by the air pressure and the throttle valve clrcuit is closed at the point 76.

When the air valve circuitis broken however, and the magnet 62 is denergized to open the valve. and cause the whistle to be sounded, the said valve automatically relieves the pressure in the branch pipe 7 8, and the time switch commences to fall. A predetermined time after the sounding of the whistle the time switch by reason of this sequential action causes a break in the throttle controlling circuit at the point 76. This causes the magnet valve 77 to be deenergized and the fluid under pressure in the pipe 69, flows through the said magnet tit recording cloc valve and actuates the throttle controlling device 79 which acting upon the throttle lever 83 shuts off the motive power. 'And the brakes may then be applied by the admission of fluid under pressure to the brake controlling valve 87. From this it will be understood that signals announcing the existence of any danger are first given to the engineer, a predetermined length of time after the rendering of such signals the motive power is shut oil and then the brakes are applied to bring the train to a standstill. The signals are preferably both audible and visual so that the engineer cannot fail to receive them and a check; onthe actions of the engineer is kept by means ofthe this'clock serving in the manner fore described, to record the v 'ving of the signal and ,also by, means 0 an additional wire?88,-terminating in a contact 89, to beenga d by the. time switch when the same has ecu-actuated, to record the-time at which the throttle is closed and the brakes are set. This circuit for recording the actuation of the means for controlling the train is completed from the magnet to the common return wire 56, bymeans of the Wire 88, circuit wire 7 4-66, battery .65, and the wire 59, common to both magnets.

With the use of my system, if a train is in a block a signal will be sent back to the next two sections in rear, giving warning of the occupancy of the said block to any approaching trains and if such warnings are not heeded by the approaching trains, the

train controlling devices will operate to stop the approaching trains in time to avert an accident. If for any reason any of the circuits should be broken either accidentally or otherwise, warning of this defect would be communicated to the approaching trains in the same way. Such warnings are all conveyed to the trains by reason of the rupture in the shunt circuit and as this shunt circuit is subject to all track and circuit conditions it will be evident that a defect of any character in either the track or the different circuits, will cause notice to be given of such. defects. As the track circuits are all normally closed circuits as soon as the block is cleared or the defect is remedied, the-cira cuits will automatically-resume their proper closed condition.

It is im ortant that the main block relay should e fully denergized when its batv tery is short circuited by the train in the block so that it will cause, by reasonof the dropping of itsarmature, a positive break in the shunt circuit. In order to insure the complete denergization .of the main block relay, Iprefer the use of the connections illustrated in Fig. 3, where I employ at each station a short circuitin ponductor 111, connected to the track 0 and terminating in a contact 112, in the path of the armature 22, of the local block relay. In this case the battery 113, for energizing the main block relay is connected directly across the rails and the armature 22,

not tor the additional conductor 111, when the battery is short circuited by the wheels of the train in the block, enough current might still find its way to the" main blockrelay so that the saidrelay would not be completely deenergized and would therefore fail to break the shunt circuit. The conductors ill-26 incombination with the armature 22, form a low resistance shunt in parallel with the trucks of the train to insure deenergization of the main block relay. This combined conductor Ill-26 just described, serves also as a parallel path across the rails for the shunt portion of the cab cirthe main block cuit so that a low resistance connection is also provided across the rails other than by way of the car wheels.

preferably be greater in strength than the battery 14, in the shunt connection so that if the train should be reversed and the main battery on the train and the battery in the shunt be placed in opposition, although there would be some neutralizing efiect, there would be still enough potential to energize the cab relay.

The system is also designed to give warning of the break down of the insulation be: tween any of the blocks. Suppose for instance that the joint 114, should break down. The current from the battery 14, instead of performing its usual function of energizing the relay 35, would flow across the joint 114, to the rail, thence through the shunt and back to the opposite pole of the battery. This deenergization of relay 35, would cause a second deenergization of relay 32, and signals would be sent back as before. Again supposing the joint 115 to become defective section and being in its insulation, the current from the main block battery 25, will flow by combined conductor 2638 to relay 35, through conductor 37, to the shunt conductor, by the shunt conductor, to the short block, thence to block local battery 19, across the defective joint 115, toopposite pole of battery 25. The battery 19 would be thus connected in oppo: sition and the main block relay thereby failing to receive its proper supplyo-f current would become 'deenergized and break the shunt connection at the next preceding section. This also would result in the giving of due signals to approaching trains.

The recording device recordsthe time at which "the actual train I controlling means were actuated, provided of course that such devices were actuated. The record also shows just how longthe signals were displayed and how long the actual train controlling means were in force.

For the purpose of rendering the relation of the different circuits more definite I have, in certain of the claims referred to the in- 'sulated sections in the relation of their described the main block-relay of one. section as controlling the shunt connection 'between' that section and the next preceding in turn controlled by the local block relay of the succeedingse'ct1on that is,,the. section next aheadin the direction'fof travel. In the same manner and for this same purpose of making the claims more definite and-clear, the line circuits have, for. instance, in certain claims been described as extending frorn'a certain section to the second section next preceding that particular section and terminating there in a relay controlling the shunt connection at the forward end of that second preceding section. It Wlll be apparent that the line circuits are controlled either directly or indirectly by the main and local block relays ofthe sections through which such line circuits pass. Taking for instance the line circuit 33, we find that it is controlled by the local block relays 20 of the two sections through which it passes and is also controlled by the so-called line controlling relays 35 of these same Sections. The line controlling circuits and relays being in turn controlled by the main block relays 23, it can be truthfully said that this circuit is under control of both the main and local block relays. Considerin the other line circuit 39, it will be note that this circuit is directly under the control of the one main block relay 23 at one section and under the control of the main block relay in the next preceding section through the intermcdiacy relays are controlled by the local block relays of the succeeding sections. The circuits thus interlock in a certain sense, so that broadly speaking, the line circuits are actually under the control of both the main and the local block circuits.

What is claimed, is:

1. A track divided by insulation into sections composed each of main and local blocks, a local block circuit having a relay, a shunt connection between the local block of one section and the main block of the preceding section, a main block circuit having a relay controlling the shunt and said main block circuit being under the controlof the local block relay of the succeeding section, a line circuit under the control of the main block relay and terminating in a relay contracks and through the shunt connection when the train is passing from one insulated block to another.

2. A track divided into insulated sections and each section composed of a main and a local block, a local blockcircuit having a relay, a shunt connection between the local block of onesection and the main block of the preceding section, a main block relay controlling the shunt and under the control of the local block relay of the succeeding section, a line circuit under the control of the main block relay, terminating in a relay controlling the shunt, a cab circuit completed through the track of the main blockand through the shunt when passing from a main into a local block.

3; A track divided into insulated sections and each section composed of a main and a local block, a local block circuit having a relay, a shunt connection between the local block of one section and the main block of the preceding section, a main block relay mcaeeo controlling the shunt and under the control of the local block relay of the succeeding section, and a line circuit under the control of the main block relay, terminating in a relay controlling a shunt connection. 1

4. In a train controlling system, a traffic track divided into sections composed each of a main' and a local block, a shunt connection between the local block of one section and the main block of the preceding section, a local block circuit including a relay, a main block circuit including a relay to control the shunt connection, linecircuits extending each from one section to. the second next preceding section terminating in a relay controlling the shunt connection at the forward end of said second section, a line controllin circuit in each section, said circuit inclu ing a relay, the line circuits being under the control of the local block relays and the line controlling relays.

5. In a train controlling system, a traflic track divided into sections composed each of a main and a local block, a shunt connection between the local block of one section and the main block of the adjoining section, a local block circuit'inc'luding a relay, to control the, next preceding shunt connection, line circuits extending each from one'section to the second next section terminating in a relay controlling the shunt connection at the forward end of said second section, a line-controlling circuit in each section, said circuit including a relay, the? line circuits being under the control of the local block relays and the line-controlling relays.

6. In a train controlling system, a traffic track divided into sections composed each of a main and a local block, a shunt connection between the local block of one section and the block of the preceding section, a local block circuit including a relay, a main block circuit under the control of the local block relay of the succeeding section and including a relay to control the shunt connection aforesaid, line circuits extending each from one section to the second next section terminating in a relay controlling the shunt connection at the forward end of said second section, a line-controlling circuit in each section, including a relay,

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the line circuits being under the control of the local block relays and the line-controlling relays.

7. In a rain controlling system, a traffic track divided into sections composed each of insulated blocks, shunt connections between adjoining blocks of adjacent sections, two block circuits at each section, one of the said block circuits controlling the shunt connection between a given section and the next preceding section and being in turn under the control of the unlike block circuit at the next succeeding section, a line controlling circuit at each section controlled by one of the block circuits aforesaid,.and line circuits each extending from one section to the second preceding section, terminating at said second preceding section in a relay controlling the shunt connection at the forward end of that section, one line circuit being under the control of one set of the block circuits and the line controlling circuits of two sections and the next line circuit being under control of a, block circuit of one section and the line controlling circuit of the next preceding section.

8. In a train controlling system, a traffic track divided into sections composed each of two insulated blocks, shunt connections between adjoining blocks of, adjacent sections, a block circuit at each section controlling the shunt connection between said section and the preceding section, a second block circuit at each section controlling the first block circuit at the preceding section, a line controlling circuit controlled by the first block circuit at each section, line circuits each extending from one section to the second preceding section and terminating there in a relay controlling the shunt connection at the forward end of that second preceding section, the line circuits being arranged in alternating order, with one line circuit under control of the second block circuits and the line controlling circuits of two sections and the next line circuit being under control of the first block circuit of one section and the line controlling circuit of the next section.

9. In a train controlling system, a traflic track divided into sections composed each of insulated blocks, shunt connections between adjoining blocks of adjacent sections, two block circuits at each section, one of the said block circuits controlling the shunt connection between a given section and the next preceding section and being in turn under the control of the unli-lie block circuit at the next succeeding section, a line controlling circuit at each section controlled by one of the block circuits aforesaid, line circuits each extending from one section to the second preceding section, terminating at said second preceding section in a relay controlling the shunt connection at the forward end of that section, one line circuit being under the control of like block circuits, and the line controlling circuits of two sections, and the next line circuit being under control of theblock circuit of one section and the line controlling circuit of the next preceding section, a cab circuit arranged to be normally completed through the traific tracks and through the shunt connection when the train is passing from one insulated block to another, and safety devices under control of said cab circuit.

10. In a train controlling system, a traffic track divided into sections composed each of two insulated blocks, shunt connections between adjoining blocks of adjacent sections, a block circuit at each section controlling the shunt connection between said section and the preceding section, a second block circuit at each section controlling the first block circ uit at the preceding section, a line controlling circuit controlled by the first block circuit at each section, line circuits each extending from one section to the second preceding section and terminating there in a relay controlling the shunt connection at the forward end of that second preceding section, the line circuits being arranged in alternating order, with one line circuit under control of the second block circuits and the line controlling circuits of two sections and the next line circuit being under control of the first block circuit of one section and the line controlling circuit of the next section, a cab circuit arranged to be normally completed through the traffic tracks and through the shunt connection when the train is passing from one lnsulated block to another, and safety devices under control of said cab circuit.

11. A train controlling system comprising a traflic track divided into insulated sections and each section composed of a main and local block, shunt connections between the local block of one of said sections and the main block of the adjoining section, main block relays acting to control said shunt connections, local block relays, the local block relay of one section serving to control the action of the main block relay of the adjoining section, and a cab circuit adapted to be normally completed through the traffic tracks, and through the shunt'connections when passing from one insulated section to another.

12. A train controlling system comprising a traflic track divided into insulated sections and each section composed of a main and local block, shunt connections between the localblock of one of said sections and the main block of the adjoining section, main block relays acting to control said shunt con nections,'local block relays, the local block relay of one section serving to control the action of the main block relay of the next adjoining section, line circuits extending between the sections, relays in said line circuits acting to control the shunt connections, said line circuits extending successively from one section through one or more sections and being controlled at the sections through which they pass, and a cab circuit adapted to be normally completed through the traffic tracks, and through the shunt connections when passing from one insulated section to another.

13. A trafiic track divided by insulation into sections and each section consisting of a main and a local block, a local block circuit in each section including a relay, a main block circuit in each section including a relay, a shunt connection extending from the local block of one section to the main block of the preceding section, said shunt connection being under the control of the main block relay of the first mentioned section, a line controlling circuit under the control of each main block relay, said line controlling circuits each including a relay, a line circuit extending from the first-mentioned section to the second preceding section and terminating there in a relay controlling the shunt connection at the forward end of that section, said line circuit being under the control of the main block relay of the firstmentioned section and the llne controlling relay of the preceding section, a second line circuit extending from the succeeding section through the first-mentioned section to the preceding section and there terminating in a relay controlling the shunt connection at the forward end of said preceding section, said second line circuit being under the control of the local block relays of the said succeeding and'said first mentioned sections and under the control of the line controlling relays of said succeeding and said first mentioned sections.

14. A trafiic track divided by insulation into sections and each section consisting of a main and a local block, a local block circuit in each section including a relay, a main block circuit in each section including a relay, said main block relay being under the control of the local block relay of the succeeding section, ashunt connection ex tending from the local block of one section to the main block of the preceding section, said shunt connection being under the control of the main block relay of the first mentioned section, a line controlling circuit under the control ofeach main block relay, said line controlling circuits each including a relay, a line circuit extending from the first-mentioned section to the second preceding section and terminating there in a relay controlling the shunt connection at the forward end of that section, said line circuit being under the control of the main block relay of the first-mentioned section and the line controlling relay of the preceding section, a second line circuit extending from the succeeding section through the firstmentioned section to the preceding section and there terminating in a relay controlling the shunt connection at the forward end of said preceding section, said second line circuit being under the control of the local block relays of the said succeeding and said first-mentioned sections and under the control of the line controlling relays of said su ceeding and said first-mentioned sections. 15. A traffic track divided by insulation into sections and each section consisting of lit tllti nsane a main and a local block, a local block circuit in each section including a relay, a main block circuit in each section including a relay, a shunt connection extending from the local block of one section to the main block of the preceding section, said shuntconnection being under the control of the main block relay of the first-mentioned section, a line controlling circuit under the control of each main block relay, said line controlling circuits each including a 'relay, a line circuit extending from the first-mentioned section to the second preceding section and terminating there in; a relay controlling the shunt connection atthe forward end of that section, said line circuit being under the control of the main block relay of the first-mentioned section and the line controlling relay of the preceding section, a second line circuit extending from the succeeding section through the first-mentioned section to the preceding section and thereterminating in a relay controlling the shunt connection at the forward end of said preceding section, said second line circuit being under the control of the local block relays of the said succeeding and said first-mentioned sections and under the control of the line controlling relays of said succeeding and said first-mentionedsections, and a cab circuit adapted to be normally completed through the traffic tracks and through the shunt connections when passing from one insulated section to anothertft '16. A traflic track dividedbyfihsulation into sections and eachgjsection donsistin a main and a local block, a local block or:

cuit in each section including a relay, as main block circuit in each se'ction includlng a relay, said main block relay being under the control of the local blockrelay of the succeeding section, a shunt connection extending from the local blockof one section to the main block of the preceding section, said shunt connection being under the con trol of the main block relay of the first-mentioned section, a line controlling circuit under the control of each main block relay, said line controlling circuits each including a relay, a line circuit extending from the first-mentioned section to the second preceds ing section and terminating there in a relay controlling the shunt connection at the for- Ward end of that section, said line circuit being under the control of the main block relay of the first-mentioned section and the line controlling relay of the preceding section, a second line circuit extendingfrom the succeeding section through the first-mentioned section to the preceding section and there terminating in a relay controllin the shunt connection at the forward end 0 said precedin section, said second line circuit -being un er the control of the local block relays of the said succeeding and said first cuit in each section including a relay, a

main block circuit in each section including a relay, a shunt connection extending from the local block of one section to the main block of the preceding section, said shunt connection being under the control of the main block relay of the first-mentioned sectlon, a 'l1ne circuit extending from the firstmentioned section to the second preceding section and terminating there in a relay controlling the shunt connection at the forward end of that section, said line circuit bemg under the control of the'main block relays of the first-mentioned section and of the section preceding the first mentioned section,

a second line circuit extending from the succeeding section through the first-mentioned section'to the section preceding the same and terminating there in a relay controlling the shunt connection at the forward end of said preceding section, said second line circuit being under thecontrol of'the main and local blockrelays of the said succeeding and first-mentioned sections.

18. A trafiic track divided by insulation into sections and each section consisting of -.-a'main' and a local block, a local block circuitx in each section including a relay, a main blockcircuit in each section including a relay, a shunt, connection extending from the local'block of one section to the main block of the preceding section, said shunt connection being under the control of the main block relay of the first-mentioned section, a line circuit extending from the firstmentioned section to the second preceding section and terminating there in a relay controlling the shunt connection at the forward end of that section, said line circuit being under the control of the main block relays of the first-mentioned section and of the section preceding the, first-mentioned section, a second line circuit extending from the succeeding section through the first-mentioned section to the section preceding the same and terminating there in a relay controlling the shunt connection at the for- Ward end of said preceding section, said second line circuit beine under the control of the main and local block relays of the sald succeeding and first-mentionedsections, and

- the shunt connections when passing from one insulated section to another.

19. A traffic track divided by insulation into sections, each section consisting of a main and a local block, a local block circuit in each section including a relay, a main block circuit in each section including a relay, said main block relay being under the control of the local block relay of the succeeding sectionga-jshunt connection extending between the local block of one section and the main block of the preceding section,

said shunt connection being under the control of the main block relay of the first-mentioned section, and line circuits extending between the difierent sections controlled by the main and local block relays and terminating in relays controlling the shunt connections between the different sections.

20. A-traflic track divided by insulation into sections, each section consisting of a main and a local'block, a local block circuit in each section ificludin a relay, a main block circuit in each section including a relay, said main block relay being under the control of the local block relay of the succeeding section, a shunt connection extendng between the local block of one section nd the main block of the preceding section, said shunt connection being under the control of the main block relay of the first-mentioned section, line circuits extending between the different sections controlled by the main and local block relays and terminating in relays controlling the shunt connections between the different sections, and a cab circuit. adapted to be normally completed through the trafiic tracks and through the shunt connections when passing from one insulated section to another. U f

21.- In a train controlling system,- a' ;t rafiic track divided into sections composed each of insulated blocks, shunt connections between the adjoining blocks of adjacent sections, main block relays acting to control said shunt connections, local. block relays, the

local block relay of one-section serving to control the action of the main block relay of the next adjoining section, line circuits extending between the sections, relays in said line circuits acting to control the shunt connections, said line circuits extending successively from one section through one or more "sections and being controlled at the sections "through which theypass.--

22. A train controlling system comprising a traffic track divided into sections composed each of insulated blocks, shunt connections between the adjoinin blocks of adjacent sections, main block re ays actin to control said shunt connections, local b ock relays, the local block relay of one section serving to control the action of the main block relay of the next adjoining section, line circuits extending between the sections, relays in said line circuits acting to control the shunt connections, said line circuits extending successively from one section through one or more sections and being controlled at the sections through which they pass, and a cab circuit adapted to be normally completed through the trailic tracks and through the shunt connections when passing from one insulated section to another.

section to the second preceding section and terminating there in a relay controlling the shunt connection at the forward end of said second preceding section, the said line circuits being under the control of the main and local block relays in the sections in which the respectivejline circuits originate and through which they pass.

24. In a train controlling system, a trafiic track divided by insulation into sections and each section consisting of a main and a local block, a local block circuit in each section including a relay, a main block circuit in each section including a relay, a shunt connection between the local block of one section and the main block of the preceding section, said shunt connection being under the control of the main block relay of the first-mentioned section, line circuits extending from one sectionito the second preceding section and terminating there in a relay controlling the shunt connection atthe forward end of said second preceding section, the said line circuits being under the control of the main and local block relays in the sections in which the respective line circuits originate and through which they pass, and a cab circuit arranged to be normally completed through the trafiic tracks and through the shunt connections when passing from one insulated section to another.

Signed at Pittsburgh, in the county of Allegheny and State of Pennsylvania, this 22nd day of September, A. D. 1908.

* GUY P. THURBER. 

